LocalPortForwarder interrupts its thread on close()

src/main/java/net/schmizz/sshj/connection/channel/direct/LocalPortForwarder.java

@@ -107,6 +107,7 @@ public class LocalPortForwarder {
     private final Connection conn;
     private final Parameters parameters;
     private final ServerSocket serverSocket;
+    private Thread runningThread;
 
     public LocalPortForwarder(Connection conn, Parameters parameters, ServerSocket serverSocket, LoggerFactory loggerFactory) {
         this.conn = conn;
@@ -132,10 +133,20 @@ public class LocalPortForwarder {
      *
      * @throws IOException
      */
-    public void listen()
-            throws IOException {
+    public void listen() throws IOException {
+        listen(Thread.currentThread());
+    }
+
+    /**
+     * Start listening for incoming connections and forward to remote host as a channel and ensure that the thread is registered.
+     * This is useful if for instance {@link #close() is called from another thread}
+     *
+     * @throws IOException
+     */
+    public void listen(Thread runningThread) throws IOException {
+        this.runningThread = runningThread;
         log.info("Listening on {}", serverSocket.getLocalSocketAddress());
-        while (!Thread.currentThread().isInterrupted()) {
+        while (!runningThread.isInterrupted()) {
             try {
                 final Socket socket = serverSocket.accept();
                 log.debug("Got connection from {}", socket.getRemoteSocketAddress());
@@ -162,6 +173,7 @@ public class LocalPortForwarder {
         if (!serverSocket.isClosed()) {
             log.info("Closing listener on {}", serverSocket.getLocalSocketAddress());
             serverSocket.close();
+            runningThread.interrupt();
         }
     }
 

src/test/groovy/com/hierynomus/sshj/connection/channel/direct/LocalPortForwarderSpec.groovy

@@ -0,0 +1,55 @@
+/*
+ * Copyright (C)2009 - SSHJ Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.hierynomus.sshj.connection.channel.direct
+
+import com.hierynomus.sshj.test.SshFixture
+import net.schmizz.sshj.connection.channel.direct.LocalPortForwarder
+import org.junit.Rule
+import spock.lang.Specification
+
+class LocalPortForwarderSpec extends Specification {
+  @Rule
+  SshFixture tunnelFixture = new SshFixture()
+
+  @Rule
+  SshFixture realServer = new SshFixture()
+
+  def "should not hang when disconnect tunnel"() {
+    given:
+    def client = tunnelFixture.setupConnectedDefaultClient()
+    client.authPassword("test", "test")
+    def socket = new ServerSocket(0)
+    def lpf = client.newLocalPortForwarder(new LocalPortForwarder.Parameters("localhost", socket.getLocalPort(), "localhost", realServer.server.port), socket)
+    def thread = new Thread(new Runnable() {
+      @Override
+      void run() {
+        lpf.listen()
+      }
+    })
+
+    when:
+    thread.start()
+
+    then:
+    thread.isAlive()
+
+    when:
+    lpf.close()
+
+    then:
+    socket.isClosed()
+  }
+}